So many steps... I'll try to remember for you: Here's how I did it, as far as I can remember. I'll bet you I could have taken a simpler road, but this worked for me:
1- I created a snapshot (that's the simple part)! On the Mac that's in .png format and that's good because it's one of the formats that works.
2- I opened an account (free) at ImageShack.com
3- After registering and responding to the confirmation email, I uploaded my snapshots.
4- I selected one of the snapshots (on the ImageShack site, in my profile) and selected, in the "Action" box on the right-hand side the option "Get code for email". That opened a dialog box that contains a URL. Clicked on that once and it got selected; once selected, I copied it.
5- Here's what my URL looked like: http://imageshack.us/photo/my-images/713/tomorrowdatecontextprio.png/
Notice how the number "713" is embedded in the middle of the URL? That's about to change.
6- I then opened a new tab (or a new window if you prefer) in my browser and pasted the URL in the address box (the place where URLs go) and hit "Enter". This opened a page, at ImageShack, that had the image of my snapshot right in the middle!
7- I right-clicked on the image of my snapshot and this opened a dialog box with a URL, but this time, the number "713" (in my example) has been moved to the front of the URL which now looked like this: http://img713.imageshack.us/img713/8521/tomorrowdatecontextprio.png. THIS is the URL that I used in the "img" HTML tag in my post. It looked like this: